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Discussion Starter #1
Timing is set of 30 BTDC, the car starts up, idles well.
Drive the car at 2000 RPM starts to hesitate.

When we set the timing to 0 - 5 BTDC, the car is very very hard to start, won't idle etc.. etc.. etc..

I think the dizzy is one tooth off giving us these problems, what do you all think?
Motor:
1978 302
1965 Heads
Mild Crane cam
Edlbrock carb
 

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Perhaps timing sprocket/chain but why dizzy....it is just related to where the rotor points to the cap and to work around that you can crank the dizzy housing around or move the wires where they are plugged into the cap. John
 

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one of the reasons I think it might be off a tooth, is for the car to run at all, the #1 spark plug is sitting at the 12 oclock posistion. which is 30 degree below top dead ceneter according to timing light. If the whole assembly was picked up and dropped one tooth clockwise, the #1 would sit closer to the 1-2 oclock position that it should be at.
 

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My opnion...it doesnt matter how the dizzy shaft is synched to the rest of the engine....the dizzy body still has to be aimed to get the right timing.


If you move it a tooth and then time it so it'll run, the timing light will still read the same.


The cam timing could be off.....I'd check the basics first.
 

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Cam timing set right?

Is it possible that the harmonic balancer has slipped, not a normal problem but it has happened before.
 

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Discussion Starter #7
Well here is the kicker.
AS it was the car ran great up to about 2300 until it got some major hesitation, with the timing at 30 below.
When we moved it to 5 below (factory) it stay running.

So I moved the dizzy one tooth, set the timing to 20 below and it runs like a raped ape up to 5500. Other tweaks adjusted idle screw on carb and made sure that a certain someone named studio pet wasn't either keeping his foot on the gas or pulled the manual choke cable ;)
 

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Cam?, Damper?, Dist.?, etc., etc... start a basic engine timing check assuming nothing.

Before a lot of labor, check the easy stuff-- dwell, cap, rotor, plugs, wires, etc for problems. Run it at night or with the lights off to check for arcing from the wires. If the rotor and cap are not by the same manufacturer, they'll have problems (I know).

Pull all the plugs, it makes the engine easier to turn by hand, which is what I'm going to ask you to do.

Identify exactly when #1 cyl is at TDC. If you have a dail indicator, GREAT!, if not, you can get it pretty darn close. Turn the engine to where it's TDC on the balancer, make sure this is the compression stroke by looking at the Dist. Back it off 30 degrees or so. Stick a long shafted screw driver through the #1 plug opening to where it's standing as close to vertical, relative to the head, as possible. Bend a wire where it will stand on it's own. If you have a dail indicator situate it to measure the rise in the screwdrive(or shaft). Slowly rotate the crank towards TDC noticing, by sight or feel or dail, the screwdriver raising. AT the point it stops raising, STOP. Put a mark on the balancer. Repeat two more times to make sure you identify the same point, repeat as nesessary to get three good readings. Move the crank to 30 degrees past TDC, and repeat the process, only approaching TDC from the back side. Don't worry if the two marks don't coincide, they won't if you're going off your sight, but they will be close. TDC will be at the midpoint between your two marks.

Does your physically determined TDC coincide with the TDC on the balancer? If yes, the balancer is OK. If not, your balancer has most likely rotated on the rubber dampening ring, and your TDC mark sould be the basis for timing. Buy a timing tape and apply it to the dampner-- it's the easiest, longest lived way to mark the new timing marks; Make sure it's TDC aligns with YOUR marks.

A fairly stock motor should have an initial timing between 6 & 8 degrees BTDC. High performance cams may like it better at 12 BTDC; rarely, rarely will you need to go as high as 15 BTDC. If you have to go to 15, you may want to consider advancing the cam timing for street use.

If the dampner was OK, you can check the cam timing to verify whether it's off a tooth using the dail indicator positioned on the top of the rocker arm, above the push rod. Get the cam specs, and basically degree the cam to check it's operating according to spec. You'll need to have a timing tape on the harmonic to do this.

Verify these two things and call me in the morning... Tom's epistle for now.
 

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one of the reasons I think it might be off a tooth, is for the car to run at all, the #1 spark plug is sitting at the 12 oclock posistion. which is 30 degree below top dead ceneter according to timing light. If the whole assembly was picked up and dropped one tooth clockwise, the #1 would sit closer to the 1-2 oclock position that it should be at.
I think we may all be a bit confused by terminology being used. Talk about #1 spark plug sitting at 12-1-2 o'clock position is confusing as well. I think you are looking at the distributor when you are making these observations. Then, the timing light being 30 degrees below, etc, is confusing.

If I'm reading you right, you're equating distributor cap position with the timing. Timing is what the light says it is, period.

First of all, don't worry where the wires are in the cap. As long as the firing order is correct, and the timing can be adjusted without the vacuum advance cannister hitting something, it's good to go!

Second: timing is before TDC (BTDC), or after TDC (ATDC), not above or below. It must be timed BTDC. If the dampener has slipped, you are in the dark as to where it's actually setting. Frankly, from your description, I'm not sure what you're doing.

When you had it 30 degrees below (I assume this is BTDC?), one sure way to tell if it's too advanced, is to take it on the road and see if it pings at 40-50 mph when under a load. If it doesn't, the dampener has probably slipped since it should rattle big time with that much advance on it. I am also assuming that you had the VA line disconnected and the port plugged on the carb when timing it.

I hope this helps a little.
 

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Discussion Starter #10
The problem wasn't pinging.
The problem was hesitation, hit the 2300 and the car just about died and felt like it didn't want to run.

Regardless of what the actual problem was, my persistant tinking fixed it ::

It starts right up, idles good, doesn't appear to be dumping gas, no smoke, and pulls up past 5k.

I may have used some of the terminology improperly.
I couldn't get enough adjustment in the dizzy becuase of interference. When I moved it a tooth, I was able to get it the adjustment area I wanted. Alls well that ends well.
 

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Regardless of what the actual problem was, my persistant tinking fixed it.
That's what counts! I wan't trying to give you a hard time, just thought that some folks (myself included) might not be able to offer salient suggestions if we misunderstood the situation. Glad you got it back on the road and running good!
 

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So it's fixed?
 

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Discussion Starter #13
Yup, runs good.
With some good timing advise, I will give it another shot with the light and set the initial and total all scientific like
 
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